Light-emitting Diode (LED) is a solid state semiconductor element comprising a p-n junction formed between a p-type semiconductor layer and an n-type semiconductor layer. When imposing a certain level of forward voltage to the p-n junction, holes from the p-type semiconductor layer and electrons from the n-type semiconductor layer are combined to release light. The region for light releasing is generally called light-emitting region.
The primary features of an LED include its small size, excellent CRI, high reliability, high efficiency, long life, and short initial illumination time. So far, LEDs have been applied to electronic devices, vehicles, signboards, and traffic signs. Along with the launch of the full-color LED, LED has gradually replaced traditional lighting apparatus such as fluorescent lights and incandescent lamps.
Each of the foregoing LED can be further connected to a submount via a substrate of the foregoing LED and solders or adhesive elements. Moreover, the submount includes at least a circuit to be electrically connected with a contact of a light-emitting device or a light-absorbing device via a conductive structure such as wire lines.